Question

A car of mass 1000kg travels at 12m/s on a horizontal surface and the resistance to motion is 500N .calculate power developed by the engine

Answer 1

1) momentum=mass ×velocity. mass=1000kg. velocity =12m/s

p=m ×v

p =1000kg ×12m/s

p= 12000kg/m

2). kinetic energy=1/2 m(v) square

ke =1/2 ×1000×12 square

ke =1×500×12×12

ke =72000 joule

3) power=force ×velocity

p= F×V

p= 500N×12/s

p =6000watt